The Memphis appeal. [volume] (Memphis, Tenn.) 1886-1890, 1887-02-27

able part of their course, turned
backward toward their source. AL
though the coloniIing OF the district
had lust begun, the area Of country
already cleared by settlers which was
converted into morasses by the
shock, was so great that the govern
meat was compelled to furnish some
hundreds Of thousand acres of new
lands on higher ground to those
whose dwelling places had been
made uninhabitable. 1t seems like
ly that an area OF not less than 5000
square miles was, ON the average,
though irregularly, lowered to the
depth OF tea feet below its original
level. The energy Of these shocks
was SO great that the low, strongly
built cabins of the frontiersmen
we're wrecked, the forest trees we're
bea en- against each other, and their
branches interlocked as they swung
to and fro. The irregular move
ments Of the ground led to the for
nation OF numerous great crevicts,
from which turbid waters we're
thrown up to considerable hight.
To protect themselves from being
engulfed in these assures, the people
felled trees so that they lay on the
ground at right angles to
the general tend OF the ifs.
sures, and built places of
refuge on the broad foundations
which they thus secured. There
can be no question that a disturb
ance OF this magnitude would, in the
present condition of the region where
il occurred, cause greater destruction
than did that which recently
occurred at Charleston, s. c. These
two series of shocks, that of 1911 aud
1886, have a close general relation
to each other; so alike are they, in
deed, as to suggest that the great
series OF repeated shocks, gradually
diminishing in intensity, may be the
type of disturbances characteristic
OF the low land districts of the south
ern part of this continent. The
New Madrid earthquake OF 1871 was,
however, by far the most extended
phenomenon; the shocks were more
frequent and of much greater VIC
lence, and the period during which
they REQUIRED was far longer than in
the Carolinian disturbances.
THE DANGERS FROM EARTHQUAKE
1t is satisfactory to find that, with
in the area of the United States, two
centuries of historic record go to
show that great earthquakes are ex-
ceptional, but this should not blind
US to the fact that large areas are al
ready known to have suffered from
movements which may bring wide
spread destruction where the builder
takes no account of any other dis
turber of stability save gravitation.
1t is not likely that we as yet know
by experience the full extent Of
country which is subject to this or
der of shocks; our historic perspective
is very short, and the natural evil
dence does not give us any assurance
concerning disturbances OF this lesser
order. 1t is clear that we cannot, in
this country, reckon on earth as sta
BILE as that of the northern region
of Europe, where our race
was bred and our building
system developed 1t is equally
clear that the mode Of construction
should be adapted TO the new needs
which the less firm ground OF this
country imposes on US. As long as
the building material most commonly
in use was timber, and the masonry
structures of low and substantial
nature, they were fairly fitted to af-
ford the resistance required to with
stand the shocks which could be ex-
pected to come upon them. But the
combination of ambition and econ
omy which is filling the land with
lofty and flimsy structures, invites
calamity ON the least disturbance of
the earth. Tho shock of 1855,
which did little more than stir the
fears, shake down the chimney tops
of the old town OF Boston, and afford
text for many interesting sermons,
would be extremely disastrous to the
higher and weaker structures OF to-
day. The prescriptions which the
architect has to follow in preparing
his buildings to resist the strains Of
moderate earthquake are sim
pie, and do not require any
great increase in the course of con
struction. IL is we'll to understand
that the actual movement of the
ground, even in violent shocks, is
slight. In those which we have
termed OF the first order it is doubt
full il the movement ever amounts to
a foot in amplitude, while the shocks
which we may anticipate in this
country, such as have recently oc4
Cured in Charleston, for instance,
probably swing the earth to and FRO
within the space of an inch. The
destruction is done in part by the
suddenness Of the TO and FRO motion,
which breaks the foundation from
the superstruoture, but in a larger
measure by the pendulum like vibra-
ton which is set up in the building.
This pendulum movement may cause
an oscillation of one inch at the fouh-
dations to be several feet in sixth
floor, or, say 100 feet above the
ground. The rendiug effect of this
pendulum like swinging, especially
in weak masonry, may easily be i'm
agined. .|
Arranging the scale OF Wages.
Dtrraoupn pa Eahruaru 0h-Tha